Electromagnetic waves have been used in various applications to supply energy to objects. In the case of radio frequency (RF) radiation for example, electromagnetic energy may be supplied using a magnetron, which is typically tuned to a single frequency for supplying electromagnetic energy only in that frequency. One example of a commonly used device for supplying electromagnetic energy is a microwave oven. Typical microwave ovens supply electromagnetic energy at or about a single frequency of 2.45 GHz.
Applying EM energy to an energy application zone, e.g. a microwave cavity, at a resonant frequency, such as a resonant frequency of a microwave cavity, may result in excitation of a standing wave having local maxima and minima at a constant position in the cavity. Such a standing wave may result in a non-homogeneous energy distribution in the cavity.